Administrator Guide

Error-cause Values
It is possible that a Dynamic Authorization Server cannot honor Disconnect Message request or CoA request packets for some
reason.
The Error-Cause Attribute provides more detail on the cause of the problem. It may be included within CoA-Nak and
Disconnect-Nak packets.
The following table describes various error causes for the CoA and DM requests:
Table 100. Error-cause Values
Serial
Number
Error-cause Scenarios
1 Unsupported Attributes(401)
● CoA or DM request containing one or more unsupported attributes.
● DM requests containing attributes other than NAS/Session identification
attributes.
2 Invalid Attribute Value(407)
● CoA or DM request containing the incorrect NAS-Port, calling-station-id, and
Vendor-Specific attribute values.
3 NAS Identification
Mismatch(403)
● CoA request containing NAS-IP-Address or NAS-IPV6-Address that does not
match NAS.
4 Administratively
Prohibited(501)
● NAS is configured to ignore the CoA or DM request. Also, dot1x is not
configured on the NAS-Port.
5 Session Context Not
Found(503)
● CoA or DM request containing session identification attributes that does not
match any of the NAS user sessions.
6 Resource Unavailable(506)
● Internal CoA or DM message processing errors.
7 Missing Attribute(402)
● CoA or DM request without Vendor-specific attribute or invalid Vendor-
specific attribute.
● CoA with re-authenticate or terminate request not containing calling-station-
id or NAS-Port attribute.
● CoA with disable-port or bounce-port request not containing NAS-Port
attribute.
● DM request not containing user-name attribute.
CoA Packet Processing
This section lists various actions that the NAS performs during CoA packet processing.
The following activities are performed by NAS:
● responds with CoA-Nak, if no matching session is found for the session identification attributes in CoA; Error-Cause value is
“Session Context Not Found” (503).
● responds with CoA-Nak, for any internal processing error in NAS; Error-Cause value is “Resources Unavailable” (506).
● ignores attributes that are supported as per RFC but irrelevant to the CoA operations.
● responds to a CoA-Request containing one or more incorrect attribute values with a CoA-Nak; Error-Cause value is “Invalid
Attribute Value” (407).
NOTE:
The Invalid Attribute Value Error-Cause is applicable to following scenarios:
○ if the CoA request contains incorrect Vendor-Specific attribute value.
○ if the CoA request contains incorrect NAS-port or calling-station-id values.
● rejects the CoA-Request containing NAS-IP-Address or NAS-IPV6-Address attribute that does not match the NAS with a
CoA-Nak; Error-Cause value is “NAS Identification Mismatch” (403).
● responds with a CoA-Nak, if it is configured to prohibit honoring of corresponding CoA-Request messages; Error-Cause
value is “Administratively Prohibited” (501).
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